317B

LT1317 LINER

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Technical content

Burst Mode is a trademark of Linear Technology Corporation. , LTC and LT are registered trademarks of Linear Technology Corporation. Figure 1. 2-Cell to 3.3V Boost Converter

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A UGWA WU WARBSOLUTEX I T I S Operating Temperature Range WU UPACKAGE/ORDER I FOR ATIO ORDER PART NUMBER V C FB SHDN GND LBO LBI V IN SW TOP VIEW MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 125°C, θJA = 160°C/W TOP VIEW LBO LBI V IN SW VC FB SHDN GND S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 125°C, θJA = 120°C/W SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IQ Quiescent Current Not Switching, V SHDN = 2V (LT1317) l 100 160 µA VSHDN = 0V (LT1317/LT1317B) l 25 40 µA VSHDN = 2V, Switching (LT1317B) 4.8 6.5 mA VSHDN = 2V, Switching (LT1317B) l 7.5 mA VFB Feedback Voltage 1.22 1.24 1.26 V l 1.20 1.24 1.26 V IB FB Pin Bias Current (Note 2) l 12 60 nA Input Voltage Range l 1.5 12 V gm Error Amp Transconductance ΔI = 5µA l 70 140 240 µmhos AV Error Amp Voltage Gain 700 V/V Maximum Duty Cycle l 80 85 % Switch Current Limit (Note 3) V IN = 2.5V, Duty Cycle = 30% 710 800 1300 mA VIN = 2.5V, Duty Cycle = 30% l 660 1350 mA Burst Mode Operation Switch Current Limit Duty Cycle = 30% (LT1317) 275 mA fOSC Switching Frequency l 520 620 720 kHz ELECTRICAL C CHARA TERISTICS Commercial Grade V IN = 2V, VSHDN = 2V, TA = 25°C, unless otherwise noted. Consult factory for Military grade parts. MS8 PART MARKING S8 PART MARKING LT1317CS8 LT1317BCS8 LT1317IS8 LT1317BIS8 1317 1317B 1317I 1317BI LTHA LTHB LT1317CMS8 LT1317BCMS8 (Note 1)

ELECTRICAL C CHARA TERISTICS Commercial Grade V IN = 2V, VSHDN = 2V, TA = 25°C unless otherwise noted. Industrial Grade V IN = 2V, VSHDN = 2V, – 40°C ≤ TA ≤ 85°C unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IQ Quiescent Current Not Switching, V SHDN = 2V (LT1317) l 160 µA VSHDN = 0V (LT1317/LT1317B) l 40 µA VSHDN = 2V, Switching (LT1317B) l 7.5 mA VFB Feedback Voltage l 1.20 1.26 V IB FB Pin Bias Current (Note 2) l 80 nA Input Voltage Range l 1.7 12 V gm Error Amp Transconductance ΔI = 5µA l 70 140 240 µmhos Maximum Duty Cycle l 80 % Switch Current Limit (Note 3) V IN = 2.5V, Duty Cycle = 30% l 550 1350 mA fOSC Switching Frequency l 500 750 kHz Shutdown Pin Current V SHDN = VIN l 0.1 µA VSHDN = 0V l –7 µA LBI Threshold Voltage l 180 220 mV LBO Output Low I SINK = 10µA l 0.25 V LBO Leakage Current V LBI = 250mV, VLBO = 5V l 0.1 µA LBI Input Bias Current (Note 4) V LBI = 150mV l 60 nA Switch Leakage Current V SW = 5V l 3 µA Switch VCE Sat I SW = 500mA l 400 mV Reference Line Regulation 1.8V ≤ VIN ≤ 12V l 0.15 %/V SHDN Input Voltage High l 1.4 6 V SHDN Input Voltage Low l 0.4 V SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Shutdown Pin Current V SHDN = VIN l 0.015 0.06 µA VSHDN = 0V l –2.3 –6 µA LBI Threshold Voltage 190 200 210 mV l 180 200 220 mV LBO Output Low I SINK = 10µA l 0.15 0.25 V LBO Leakage Current V LBI = 250mV, VLBO = 5V l 0.02 0.1 µA LBI Input Bias Current (Note 4) V LBI = 150mV l 54 0n A Low-Battery Detector Gain 1M Ω Load 2000 V/V Switch Leakage Current V SW = 5V l 0.01 3 µA Switch VCE Sat I SW = 500mA 300 350 mV l 400 mV Reference Line Regulation 1.8V ≤ VIN ≤ 12V l 0.08 0.15 %/V SHDN Input Voltage High l 1.4 6 V SHDN Input Voltage Low l 0.4 V Note 2: Bias current flows into FB pin. Note 3: Switch current limit guaranteed by design and/or correlation to static tests. Duty cycle affects current limit due to ramp generator. Note 4: Bias current flows out of LBI pin. The l denotes specifications which apply over the full operating temperature range. Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired.

TYPICAL PERFOR A CE CHARACTERISTICSUW INPUT VOLTAGE OSCILLATOR FREQUENCY (kHz) 700 650 600 550 500 2468

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25°C –40°C 85°C Oscillator Frequency DUTY CYCLE (%) 0 2 04 06 08 0 1 0 0 SWITCH CURRENT (mA)

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VIN = 2V L = 10µH Burst Mode Current Limit (LT1317) Switch Current Limit, Duty Cycle = 30% SWITCH CURRENT (A) 0 0.2 0.4 0.6 0.8 1 SWITCH VOLTAGE (VCESAT) (mV)

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25°C –40°C 85°C Switch Voltage Drop (VCESAT) TEMPERATURE (°C) –50 0 50–25 25 75 100 LBI INPUT BIAS CURRENT (nA)

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LBI Input Bias CurrentSwitch Current Limit TEMPERATURE (°C) –50 –25 QUIESCENT CURRENT (µA)

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Quiescent Current, SHDN = 2V TEMPERATURE (°C) –50 FEEDBACK VOLTAGE (V) 1.25 1.24 1.23 1.22 1.21 1.20 –25 0 25 50

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TEMPERATURE (°C) –50 LBI REFERENCE VOLTAGE (mV)

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–25 0 25 50 75 100 LBI Reference Voltage TEMPERATURE (°C) –50 SWITCH CURRENT (mA) 1000 900 800 700 600 500 –25 0 25 50

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DUTY CYCLE (%) SWITCH CURRENT (mA) 1200 1000 800 600 400 200 20 40 60 80

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MINIMUM (25°C) TYPICAL

TYPICAL PERFOR A CE CHARACTERISTICSUW TEMPERATURE (°C) –50 QUIESCENT CURRENT (µA) –25 0 25 50

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TEMPERATURE (°C) –50 –25 0 25 50 75 100 FB PIN BIAS CURRENT (nA)

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Quiescent Current, SHDN = 0V FB Pin Bias Current SHDN Pin Current LOAD CURRENT (mA) EFFICIENCY (%) 10 100 1000

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VIN = 3V VIN = 2.2V VIN = 1.65V LOAD CURRENT (mA) EFFICIENCY (%) 10 100 1000

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VIN = 3V VIN = 2.2V VIN = 1.65V LOAD CURRENT (mA) EFFICIENCY (%) 10 100 1000

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10.3 VIN = 3V VIN = 2.2V VIN = 1.65V 5V Output Efficiency, Circuit of Figure 1 (LT1317) 2-Cell to 3.3V Converter Efficiency (LT1317B) 2-Cell to 5V Converter Efficiency (LT1317B) Burst Mode Operation (LT1317) VOUT 50mV/DIV AC COUPLED IL 200mA/DIV VSW 5V/DIV VIN = 2V 20 µs/DIV 1317 TPC18 VOUT = 3.3V ILOAD = 30mA CIRCUIT OF FIGURE 1 Transient Response (LT1317B) VOUT 100mV/DIV AC COUPLED IL 200mA/DIV VIN = 2V 1ms/DIV 1317 TPC17 VOUT = 3.3V CIRCUIT OF FIGURE 1 WITH LT1317B Transient Response (LT1317) VOUT 100mV/DIV AC COUPLED IL 200mA/DIV VIN = 2V 1ms/DIV 1317 TPC16 VOUT = 3.3V CIRCUIT OF FIGURE 1 ILOAD 165mA 5mAILOAD 165mA 5mA SHDN PIN VOLTAGE (V) SHDN PIN CURRENT (µA) 3 5

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TYPICAL PERFOR A CE CHARACTERISTICSUW Load Regulation (LT1317) VIN = 1.5V I LOAD 25mA/DIV 1317 TPC19 VOUT = 5V VOUT 50mV/DIV DC COUPLED OFFSET ADDED Load Regulation (LT1317) VIN = 2V I LOAD 25mA/DIV 1317 TPC20 VOUT = 5V VOUT 50mV/DIV DC COUPLED OFFSET ADDED Load Regulation (LT1317) VIN = 2.5V I LOAD 50mA/DIV 1317 TPC21 VOUT = 5V VOUT 50mV/DIV DC COUPLED OFFSET ADDED Load Regulation (LT1317) VIN = 1.5V I LOAD 25mA/DIV 1317 TPC22 VOUT = 3.3V Load Regulation (LT1317) VIN = 2V I LOAD 50mA/DIV 1317 TPC23 VOUT = 3.3V Load Regulation (LT1317) VIN = 2.5V I LOAD 50mA/DIV 1317 TPC24 VOUT = 3.3V VOUT 50mV/DIV DC COUPLED OFFSET ADDED VOUT 50mV/DIV DC COUPLED OFFSET ADDED VOUT 50mV/DIV DC COUPLED OFFSET ADDED Note: For load regulation pictures, double lines are due to output capacitor ESR. VC (Pin 1): Compensation Pin for Error Amplifier. Con- nect a series RC network from this pin to ground. Typical values for compensation are a 33k/3.3nF combination. A 100pF capacitor from the V C pin to ground is optional and improves noise immunity. Minimize trace area at VC. FB (Pin 2): Feedback Pin. Reference voltage is 1.24V. Connect resistor divider tap here. Minimize trace area at FB. Set VOUT according to: VOUT = 1.24V(1 + R1/R2). SHDN (Pin 3): Shutdown. Pull this pin low for shutdown mode (only the low-battery detector remains active). Leave this pin floating or tie to a voltage between 1.4V and 6V to enable the device. SHDN pin is logic level and need only meet the logic specification (1.4V for high, 0.4V for low). PIN FUNCTIONSUU U GND (Pin 4): Ground. Connect directly to local ground plane. SW (Pin 5): Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to keep EMI down. VIN (Pin 6): Supply Pin. Must be bypassed close to the pin. LBI (Pin 7): Low-Battery Detector Input. 200mV refer- ence. Voltage on LBI must stay between ground and 700mV. Low-battery detector remains active in shutdown mode. LBO (Pin 8): Low-Battery Detector Output. Open collec- tor, can sink 10µA. A 1MΩ pull-up is recommended.

Σ RAMP GENERATOR 1.24V REFERENCE R BIAS VC gm FB ENABLE 200mV A = 2 FF COMPARATOR COMPARATOR ERROR AMPLIFIER 0.08Ω DRIVER SW GND 1317 BD Q3Q S 600kHz OSCILLATOR LBO LBI SHDN SHUTDOWN 3 (EXTERNAL) VOUT (EXTERNAL) FB APPLICATIONS INFORMATIONWU UU OPERATION The LT1317 combines a current mode, fixed frequency PWM architecture with Burst Mode micropower operation to maintain high efficiency at light loads. Operation can best be understood by referring to the Block Diagram. The error amplifier compares voltage at the FB pin with the internal 1.24V bandgap reference and generates an error signal VC. When VC decreases below the bias voltage on hysteretic comparator A1, A1’s output goes low, turning off all circuitry except the 1.24V reference, error amplifier and low-battery detector. Total current consumption in this state is 100 µA. As output loading causes the FB voltage to decrease, V C increases causing A1’s output to go high, in turn enabling the rest of the IC. Switch current is limited to approximately 250mA initially after A1’s output goes high. If the load is light, the output voltage (and FB voltage) will increase until A1’s output goes low, turning off the rest of the LT1317. Low frequency ripple voltage appears at the output. The ripple frequency is dependent on load current and output capacitance. This Burst Mode operation keeps the output regulated and reduces average current into the IC, resulting in high efficiency even at load currents of 300µA or less. If the output load increases sufficiently, A1’s output remains high, resulting in continuous operation. When the LT1317 is running continuously, peak switch current is controlled by V C to regulate the output voltage. The switch is turned on at the beginning of each switch cycle. When the sum- mation of a signal representing switch current and a ramp generator (introduced to avoid subharmonic oscillations at duty factors greater than 50%) exceeds the V C signal, comparator A2 changes state, resetting the flip-flop and turning off the switch. Output voltage increases as switch current is increased. The output, attenuated by a resistor divider, appears at the FB pin, closing the overall loop. Frequency compensation is provided by an external series RC network and an optional capacitor connected between the V C pin and ground. Low-battery detector A4’s open collector output (LBO) pulls low when the LBI pin voltage drops below 200mV. There is no hysteresis in A4, allowing it to be used as an amplifier in some applications. The low-battery detector remains active in shutdown. To enable the converter, SHDN must be left floating or tied to a voltage between 1.4V and 6V.

output voltage ripple at the expense of light load efficiency. current is stepped from 2mA to 200mA for both circuits. observed on Trace A, while none is observed on Trace B. components are listed in Table 1.

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Figure 3. Recommended Component Placement. Traces Carrying Low. Lead Length to Battery Should be Kept Short. Figure 2. LT1317 Exhibits Ripple at 2mA Load will not get advertised performance with careless layouts. Figure 3 shows recommended component placement. inability to regulate or oscillation.

Table 1. Inductors Suitable for Use with the LT1317 the Motorola MBR0520L surface mount Schottky diode.

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Figure 4. 2V to 3.3V Converter with a 10µF Ceramic Output Figure 5. Transient Response for the Circuit of Figure 4.

determining the necessary component values is given. the output voltage displays a long settling time of >5ms. time with adequate phase margin. Figure 6. Frequency Response Test Setup

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Figure 8. Reducing C to 22nF Figure 10. 3.3nF and 33k Gives the Shortest Settling Time with No Ringing. Figure 9. Using 680pF for C Results in an Figure 7. With C = 56nF and R = 33k, the System is Highly Overdamped.

ment as a low-battery detector is straightforward. Figure 12. The low-battery detector remains active in Figure 12. Accessing 200mV Reference

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Figure 11. Setting Low-Battery Detector Trip Point

1317 TA03C1, C2: AVX TPSC476M010

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22µH MBR0520 SHDN 56k 124k 1.07M 3300pF

1317 TA04L1: SUMIDA CD54-220

47µF 47µF VIN SW FB LB0 VC GND SHDN LT1317 SHUTDOWN VIN SW FB LT1317 10µH MBR0520 33k 324k 3300pF

1317 TA05L1: SUMIDA CD43-100

(2.7V TO 4.2V) 47µF 47µF SHDN VIN SW FB LT1317BCMS8 10µH D1 SHDN 33k 332k 3.3nF

1317 TA06C1: AVX TAJA156M010

C2: MURATA GRM235Y5V106Z01 L1: MURATA LQH3C100 OR SUMIDA CLQ61-100N D1: MOTOROLA MBR0520LT1 V C GND 3.3V 5V 125mA 15µF 10V 10µF CERAMIC Low Profile 3.3 to 5V Converter 5V to 12V Boost Converter 5V to 12V Boost Converter Efficiency Single Li-Ion to 5V DC/DC Converter EfficiencySingle Li-Ion to 5V DC/DC Converter LOAD CURRENT (mA) EFFICIENCY (%) 10 100

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LOAD CURRENT (mA) 1 10 100 1000 EFFICIENCY (%)

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VIN = 4.2V VIN = 3.5V VIN = 2.7V

2-Cell to 5V DC/DC Converter with Undervoltage Lockout VIN LBI SW FB LBO LT1317 10µH D1 SHDN 33k 332k 340k 100k301k 1M 3.3nF470pF

1317 TA07D1: MOTOROLA MBR0520LT1

L1: SUMIDA CD43-101 STARTS AT V IN = 1.9V STOPS AT VIN = 1.6V VC GND

2 ALKALINE

22µF 10V 100µF 10V VIN SW FB LT1317 L1A 20µH CERAMIC 10µF, 16V L1B SHDN 33k 100k 432k VOUT 4.1V 110mA 3.3nF

1317 TA08D1: MOTOROLA MBR0520LT1

L1: COILTRONICS CTX20-1 Q1: 2N3904 V C GND VIN 1.5V TO 10V 15µF 20V 47µF 10V Universal Wall Cube to 4.1V VIN SW FB LT1317/LT1317B 22µH D1 SHDN 33k 178k 8.2V 400mA 3.3nF 100pF

1317 TA09D1: MOTOROLA MBR0520LT1

L1: SUMIDA CD43-220 VC GND SHUTDOWN 22µF 16V 47µF 16V +2 Li-ION CELLS (5.8V TO 8.4V) 22pF 2 Li-Ion to 8.2V DC/DC Converter

Single Li-Ion Cell to 4V/70mA, – 4V/10mA VIN LT1317 4.5V TO 2.5V 22µH 22µH FBSHDNSHUTDOWN 33k 442k 70mA 1.00M 3.3nF 100pF C1: C2: C3: D1: D2: L1, L2: MURATA GRM235Y5V107Z01 AVX TAJB336M010 AVX TAJA156M010 MBR0520 BAT54S (DUAL DIODE) MURATA LQH3C220K04

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1µF CERAMIC 1µF CERAMIC 33µF 1µF Li-Ion CELL VC GND SW 15µF – 4V 10mA VIN SW FB LT1317B 22µH 680Ω 150pF 33k 5.9k 150k 3300pF

1317 TA11C1: AVX TAJ156M010

C2: SANYO 35CV33GX C3, C4, C5, C6: 0.1µF CERAMIC D1, D2, D3: MOTOROLA MMBD914LT1 L1: MURATA LQH3C220 V C GND VIN 3V TO 6V VOUT 33V 0mA TO 10mA 15µF 10V 0.1µF 10µF 35V 0.1µF 0.1µF 0.1µF 47Ω Low Noise 33V Varactor Bias Supply

Dimensions in inches (millimeters) unless otherwise noted. Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) MSOP (MS8) 1197 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 0.021 – 0.006 (0.53 – 0.015) 0° – 6° TYP SEATING PLANE 0.007 (0.18) 0.040 – 0.006 (1.02 – 0.15) 0.012 (0.30) REF 0.006 – 0.004 (0.15 – 0.102) 0.034 – 0.004 (0.86 – 0.102) 0.0256 (0.65) TYP 12 3 4 0.192 – 0.004 (4.88 – 0.10) 8 7 6 5 0.118 – 0.004* (3.00 – 0.102) 0.118 – 0.004 (3.00 – 0.102) 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 1 2 3 4 0.150 – 0.157 (3.810 – 3.988) 8 7 6 5 0.189 – 0.197* (4.801 – 5.004) 0.228 – 0.244 (5.791 – 6.197) 0.016 – 0.050 0.406 – 1.270 0.010 – 0.020 0°– 8° TYP 0.008 – 0.010 (0.203 – 0.254) SO8 0996 0.053 – 0.069 (1.346 – 1.752) 0.014 – 0.019 (0.355 – 0.483) 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) TYP DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE

 LINEAR TECHNOLOGY CORPORATION 1 998 13177bf LT/TP 1198 4K • PRINTED IN THE USA TYPICAL APPLICATIONU Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear-tech.com Digital Camera Power Supply 24V SHUTDOWN VIN SW FB LT1317 LPRI:15µH LA LB LC 10k 604k 10k 3300pF

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C1, C4: AVX TPSC226M016 C2: AVX TPSC106M006 C3: CERAMIC (i.e. AVX, MANY OTHERS) C5: SANYO 35CV10GX D1, D2: MBR0520LT1 (MOTOROLA) OR EQUIVALENT D3: MMBD914LT1 (MOTOROLA) OR EQUIVALENT T1: COILTRONICS CTX02-14272-X1 V C GND 3.3V 150mA 20mA 18V 3mA 22µF 10V 4 AA CELLS (3.2V TO 6.5V) 1µF, 16V SHDN 100µF 22µF 10V 10µF 35V PART NUMBER DESCRIPTION COMMENTS LTC 1163 Triple High Side Driver for 2-Cell Inputs 1.8V Minimum Input, Drives N-Channel MOSFETs LTC1174 Micropower Step-Down DC/DC Converter 94% Efficiency, 130 µA IQ, 9V to 5V at 300mA LT1302 High Output Current Micropower DC/DC Converter 5V/600mA from 2V, 2A Internal Switch, 200 µA IQ LT1304 2-Cell Micropower DC/DC Converter Low-Battery Detector Active in Shutdown LT1307 Single Cell Micropower 600kHz PWM DC/DC Converter 3.3V at 75mA from 1 Cell, MSOP Package LTC1440/1/2 Ultralow Power Single/Dual Comparators with Reference 2.8 µA IQ, Adjustable Hysteresis LTC1516 2-Cell to 5V Regulated Charge Pump 12 µA IQ, No Inductors, 5V at 50mA from 3V Input LT1521 Micropower Low Dropout Linear Regulator 500mV Dropout, 300mA Current, 12 µA IQ RELATED PARTS